Liquid leather-dressing.



GEORGE W. OHILDS,

OF NEW YORK, N. Y.

LIQUID LE ATHER-DRE SSING.

Speeificationof Letters Patent.

Patented Dec. 31, 1907.

Original application filed May 16, 1906, Serial No. 317,141. Divided and this application filed Au ust 301 1907- erial No. 390.753-

To a ZZ 107. 0m it may concern:

Be it known that I, GEORGE W. Cnltns, of

New York city, in the county and State of New York, have invented a certain new and useful Improvement in Liquid Leather- Dressings, whereof the following is a specification.

This application is a division of my application Serial #317,141 filed May 16, 1906, and the claims herein are limited to a dressing adapted for impregnating leather to increase the ultimate solidity of the latter when dried, and containing solid matter derived from sapped or exhausted organic tanning liquors. As described in my original application aforesaid, such sapped liquors being usually polluted with chemicals introduced thereto or resulting from chemical changes therein, and carrying a large percentage of non-tannic material, are termed runaway or tail liquors and are ordinarily discharged to waste from the last layer in which they have been sapped.

To produce the dressing herein claimed, I treat the spent liquor in accordance with the nature of the same, as tollows:*lf the spent liquor contains lime or lime compounds, these components may be precipi ated by the addition of chemicals l ornnng insoluble compounds with lime. For instance, amm )niu1n oxala e. sodium plgosolmte. so1liuni l'llgMQ HY i l: U0 ell1 ployed to ell'ect such precipitation. The precipitate is then settled out and the supernatant liquor run oil for further purification or concentration. It the spent liquor con tains non-volatile impurities, such as mineral acids, these may be either neutralized by the addition of alkali, such as sodp n hvdrate or potassium drate or may be DKQCI'PHZ'L! ed by the iiddit oldiases forming insoluble compounds with the acids, such as barium chlorid. Said spent liquor may thenbe heated until the volatile impuri 'i or instance, acetic or propionicol Lutyric acids, are eliminated and the resultant liquid is concentrattal, conveniently by continued heating in cacao, until it attains a specific gravity ol 1.05 to 1 The otherwise waste liquors thus purified and concentrated may be utilized to increase the solidity of leather as followsz-Hides l which have been subjected to the action of a tanning solution until they have combined with approximately all the tannin with which they will combine, are then im regnated with the concentrated waste t@1 ni ng iquor, in any convenient manner, for instancefsilch leather may be placed in a rotary drum and said concentrate, preferably lieat ed, introduced to said drum, conveniently through a hollow axle or trunnion thereof, and the revolution of said drum continued until said concentrate is absorbed by the leather and fills the pores of the latter so that When dried the residue of the liquor in the leather, not only renders the latter more solid than if it had not been impregnated with said liquor, but also adds materially to its final weight. It may be observed that if said liquors are not concentrated to substantially the consistency described, there will not be sufficient solid residue thereof when the leather is dried, to attain the result desired. Moreover, if the liquors are concentrated to a greater degree they will not be absorbed by the leather. Leather impregnated as last described may then be bleached, oiled, dried, dampened, and rolled iiitlie'usual mannrl' M I do not desireto limit myself to all the details of procedure above enumerated, as various modifications may be made therein without departing from the essential features of my invention as defined in the appended. cl aims I claim l 1. A leather dressing adapted for impregnating leather, derived from sapped or exhausted organic tanning liquor and having a specific gravity of from 1.05 to 1.3, substantially as described.

2. A leather dressing adapted for impregnating leather, containing inert solid matter derived from sapped or exhausted organic tanning liquors and having a specific gravity of from 1.05 to 1 .23, substantially as described.

In testimony whereof, I have hereunto signed my name at New York, New York, t this 26th day of August, 1907.

GEORGE l/V. CHILDS. ll itnesses:

\V. G. HORTON, F. P. PALM. 

